Hitherto, it is widely known that a mobile terminal device such as a cellular phone includes a device housing with a metallic plate integrally formed with resin to reduce size and increase strength at the same time. Such a mobile terminal device including a device housing of this type is applied to, for example, a personal computer, and is disclosed in, for example, Japanese Laid-open Patent Publication No. 9-214144.
Recent mobile terminal devices are required to be waterproof in addition to being small and having a high strength. Accordingly, as a waterproof structure of a device housing, the following structure is generally used in a mobile terminal device such as that described above. That is, in the structure, an external wall is integrally formed with resin along outer peripheral edges of a metallic plate. Thereafter a waterproof tape is adhered to an inner area of the metallic plate surrounded by the external wall. Then other members such as a panel member are adhered and secured to the metallic plate through the waterproof tape. In addition, an area situated inwardly of the waterproof tape provides space for disposing an electronic component holder for holding various electronic components such as a liquid crystal display (LCD).
Here, from the viewpoint of providing adhesive strength by the waterproof tape, a flat area is required as an area where the waterproof tape is adhered in the inner area of the metallic plate surrounded by the external wall. Therefore, in the above-described device housing, the electronic component holder has been separated from the external wall formed at the outer peripheral edges of the metallic plate, because of providing a flat area as a waterproof adhesion area between the external wall and the electronic holder. In addition, for providing such a waterproof tape adhesion area, the electronic component holder and the metallic plate, where the external wall is formed, are manufactured as separate individual components, and the electronic component holder is attached later to the metallic plate, where the external wall is formed.